Apparatus for measuring pressure



Apnl 8, 1930. c. A. SABBAH 1,

APPARATUS FOR MEASURING PRESSURE Filed April 21. 1927 7 lnQevTborz Cam" A. Scybbolq,

. l/ by HIS Abtorney.

Patented Apr. 8, 1930 CAMIL A.

SABBAH, OF SCI-IENEGTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIO COMPANY, A CORPORATION OF NEW YORK APPARATUS FOR MEASURING PRESSURE Application filed April 21,

My invention relates to apparatus for measuring the pressure of a gas or vapor, and has for its principal object the provision of an improved apparatus that is rugged in construction and may be'utilized to accurately measure pressure or to produce an elfect dependent on the pressure'within the evacuated vessel of a vapor electric device such as a mercury arc rectifier or the like.

"In the operation of vapor electric devices comprising a cathode and an anode enclosed within an evacuated vessel, it is desirable to have at all times some indication of the gaseous or vaporpressure within the evacuated vessel. It has been found that the positive ion density within such a vessel is dependent on the gaseous or vapor pressure up to a pressure of about fifty microns of mercury. .111 accordance with my invention, a current dependent on the positive ion density within the evacuated vessel is utilized to produce an indication or effect dependent on the pressure within the vessel.

Mv invention will be better understood froni the following description when considered in connection with the accompanying drawings and its scope will be pointed out in the appended claims.

Referring to the drawings, Fig 1 illustrates a mercury arc rectifier wherein my invention has been embodied; and Fig. 2 illustrates certain details of a measuring apparatus constructed in accordance with my invention.

The mercury arc rectifier illustrated by Fig. 1 comprises an evacuated vessel 1 which encloses a mercury cathode 2, a plurality of anodes 3, and an apparatus 4: adapted to transmit a current dependent on the pressure with in the vessel 1. p

[is indicated more clearly in Fig. 2, the apparatus i is provided with an auxiliary anode or electrode 5 which is connected to thecathode 2 through a source of current shown as a F battery 6 and with electrodes 7 and 8 which are located near the electrode 5, are insulated from the electrode 5 and from one another by an insulation support and are interconnected through a source 10 and a device 11. lit should be understood that the device ll may 1927. Serial No. reams.

be an indicating meter, an apparatus for controlling the operation of a vacuum pump connected to the vessel 1 or the like, and that the apparatus 4 is preferably located near one of the anodes 3 in order that the pressure in the vicinity of the anodes may be measured.

In the operation of the rectifier, the arc is started between the cathode 2 and the anodes 3 by means of a starting electrode 12 which is temporarily brought into contact with the surface of the mercury. When the arc is established between the cathode and the anodes, an arc is also started between the cathode and the electrode or auxiliary anode 5, and the spiral-shaped electrode 7 picks up positive ions at a ratejdependent on their concentration which in turn is dependent for a-given current on the vapor pressure in the vessel 1. Under these conditions the electrode 8 attracts to itself suflici-ent electrons to neutralize the positive ions which find their way to the electrode 7, and a current dependent on the vapor pressure is supplied to the device 11.

Itgvill be readily understood that my invention is not limited to the arrangement shown but may be modified to meet the dif- -ferent conditions encountered in its use.

Thus, if an anode shield insulated from the anode is utilized, the device 11 and source 10 may be connected between the shield and the wall of the vessel.

What I claim as new and desire to secure by I Letters Patent of the United States, is:

1. ,The combination of a vapor electric apparatus comprising a cathode and an anode enclosed within an evacuated vessel, current supply means connected between said cathode and anode, and means comprising a pair of electrodes insulatedfro1i1 said cathode and anode and arranged to transmit a current dependent on the positive ion density in the vapor between said cathode and anode.

2. The combination of a vapor electric apparatus comprising a cathode and an anode enclosed within an evacuated vessel, current supply means connected between said cathode and anode, means comprising a pair of electrodes insulated from said cathode and anode and arranged to transmit a-current dependent on the positive ion density in the vapor between said cathode and anode, and means connected between said electrodes for producing an effect dependent on said current.

, 3. The combination of a vapor electric a paratus comprising a cathode and. an ano e enclosed w1th1n an evacuated vessel, a source of current connected between said cathode and said anode, and means comprising a pair of electrodes insulated from said cathode and said anode and from one another and arranged to transmit a current dependent on the positive ion density within said vessel.

4. The combination of a Vapor electric apparatus-comprislng a cathode and an anode enclosed within an evacuated vessel, a source ofcurrent connected between said cathode and said anode, means comprising a pair of electrodes insulated from said cathode and said anode and from one another and arranged to transmit a current dependent on the positive ion density within said vessel, and a source of potential connected between said electrodes.

In witness whereof, I have hereunto set my hand this 20th day of April, 1927.

v CAMIL A. SABBAH. 

